Excessive lateral dental arch expansion in experimentally developed acromegaly-like rats

ObjectiveTo investigate morphological changes in the dental arches of acromegaly-like rats recently developed by means of exogenous IGF-I administration.DesignHuman recombinant IGF-I (640 μg/day) was continuously administered subcutaneously for 4 weeks by osmotic mini-pumps to 10-week-old male rats (n = 6). Control animals were injected with saline alone (n = 6). After administration, all the rats were housed for 4 more weeks. Arch width (W), length (L) and angle (θ) in the mandible and maxilla were measured once a week during and after IGF-I administration.ResultsThe concentration of circulating IGF-I, and W and θ in the mandible were significantly increased as compared with the control rats. Although the mandibular dental arch stopped expanding once administration ended, it did not return to the control size.ConclusionsIn our acromegaly-like rat model, mandibular dental arch growth is greater in the lateral than antero-posterior direction during and after IGF-I administration.